Flow Meter Well Tool

ABSTRACT

A flow meter well tool includes a volumetric well flow meter to be positioned in a wellbore. The volumetric well flow meter includes a hollow cylindrical tubing to be positioned in the wellbore. The tubing splits well fluid through the wellbore into an internal fluid through the volumetric well flow meter and an external fluid through an annulus between the wellbore and the volumetric well flow meter. The hollow cylindrical tubing includes an internal portion, where an internal cross-sectional area of the internal portion is less than an internal cross-sectional area of the hollow cylindrical tubing.

TECHNICAL FIELD

This disclosure relates to well flow meters in well systems, forexample, in downhole well tools.

BACKGROUND

Well flow meters (e.g., volumetric and pressure based flow meters) areused in well systems, such as hydrocarbon-bearing wells, to measure flowrate of a fluid in the well system. An in-well flow meter includes asensor to measure a fluid characteristic of the fluid in the wellsystem. Sometimes, an in-well flow meter is placed on or is part of awell tool on either an outlet end or inlet end of a downhole pumpingunit, for example, an electric submersible pump (ESP).

SUMMARY

This disclosure describes well flow meter systems and flow meter welltools to measure fluid characteristics, such as flow rate, fluiddensity, and flow restriction, of a fluid in a well.

Certain aspects encompass a flow meter well tool including a volumetricwell flow meter to be positioned in a wellbore. The volumetric well flowmeter includes a hollow cylindrical tubing to be positioned in thewellbore, the tubing to split well fluid through the wellbore into aninternal fluid through the volumetric well flow meter and an externalfluid through an annulus between the wellbore and the volumetric wellflow meter. The hollow cylindrical tubing includes an internal portion,where an internal cross-sectional area of the internal portion is lessthan an internal cross-sectional area of the hollow cylindrical tubing.

The aspects above can include some, none, or all of the followingfeatures. The flow meter well tool includes a discharge grill componentattached to an outlet end of the volumetric well flow meter, thedischarge grill component to commingle the internal fluid and theexternal fluid that flow past the outlet end of the volumetric well flowmeter. The discharge grill component includes a tubing attached to thehollow cylindrical tubing at the outlet end of the volumetric flowmeter, the tubing including openings through which the internal fluidflows to commingle with the external fluid. An open area of the openingsis greater than or equal to the internal cross-sectional area of thehollow cylindrical tubing of the volumetric flow meter. The dischargegrill component includes a bull nose in the tubing. The flow meter welltool includes a measurement correction component attached to thedischarge grill component, the measurement correction component tocorrect flow measurement errors introduced by tolerances of an innerdiameter of the wellbore. An outer diameter of the volumetric well flowmeter, an outer diameter of the discharge grill component, and an outerdiameter of the measurement correction component are substantially equalto each other. A longitudinal length of the volumetric well flow meteris substantially the same as a longitudinal length of the measurementcorrection component. The flow meter well tool includes a flowconditioner at an inlet end of the volumetric well flow meter tohomogenize the well fluid. The flow conditioner includes a conditionertubing with a plurality of fins arranged to homogenize the well fluid,the conditioner tubing coupled to the hollow cylindrical tubing at theinlet end of the volumetric well flow meter. The volumetric well flowmeter is positioned before an intake of a downhole pumping unit in thewellbore.

Certain aspects encompass a well flow meter system including avolumetric well flow meter positioned in a wellbore, the flow meterincluding a hollow cylindrical tubing to split well fluid through thewellbore into an internal fluid through the volumetric flow meter and anexternal fluid through an annulus between the wellbore and thevolumetric well flow meter. The well flow meter system includes aninternal sensor of the hollow cylindrical tubing to measure a pressuredifferential of the internal fluid, an external sensor of the hollowcylindrical tubing to measure a pressure differential of the externalfluid, and processing circuitry connected to the internal sensor and theexternal sensor. The processing circuitry performs operations includingreceiving pressure signals from the internal sensor and the externalsensor, determining pressure differentials across the internal fluidthrough the volumetric flow meter and across the external fluid throughthe annulus, and determining fluid characteristics of the well fluidbased on the determined pressure differentials.

The aspects above can include some, none, or all of the followingfeatures. The hollow cylindrical tubing includes an internal portion,the internal portion having a cross-sectional area less than an internalcross-sectional area of the hollow cylindrical tubing. The well flowmeter system includes a discharge grill component attached to an outletend of the volumetric well flow meter, the discharge grill component tocommingle the internal fluid and the external fluid that flow past theoutlet end of the volumetric well flow meter, and a measurementcorrection component including a tubing section and a correction sensorto measure a pressure differential of the commingled internal andexternal fluid between the measurement correction component and thewellbore. The well flow meter system includes a transmitterelectronically coupled to the internal sensor, the external sensor, andthe correction sensor, and a receiver to receive differential pressuredata from the internal sensor, the external sensor, and the correctionsensor, the differential pressure data transmitted from a transmittercoupled to the internal sensor, the external sensor, and the correctionsensor. The operations further include determining a pressuredifferential across the commingled internal fluid and external fluidflowing outside the correction sensor, where the fluid characteristicsinclude a volumetric flow rate of the commingled fluid, a volumetricflow rate of the internal fluid, a volumetric flow rate of the externalfluid, a fluid density, and a fluid flow path resistance. Determiningthe fluid characteristics of the well fluid includes solving thefollowing equations:

$Q_{A} = {A_{1}\sqrt{\frac{2\Delta \; P_{12}}{\rho \lbrack {( \frac{A_{1}}{A_{2}} )^{2} - 1} \rbrack}}}$Q = Q_(A) + Q_(B) Δ P_(xy) = (R_(B)Q_(B)² + H_(g))ρ gΔ P_(xy) = (R_(A)Q_(A)² + H_(g))ρ gΔ P_(ij) = (R_(B)Q² + H_(g))ρ g

where an internal cross-sectional area of the volumetric flow meter(A₁), the pressure differential of the internal fluid (ΔP₁₂), smallestinternal cross-sectional area of an internal portion of the volumetricflow meter (A₂), the pressure differential of the external fluid(ΔP_(xy)), the pressure differential of the commingled fluid (ΔP_(ij)),flow path resistance of the fluid through the volumetric flow meter(R_(A)), and vertical elevation change (H_(g)) are used to solve forvolumetric flow rate of the commingled fluid (Q), volumetric flow rateof the internal fluid (Q_(A)), volumetric flow rate of the externalfluid (Q_(B)), fluid density (ρ), and fluid flow path resistance(R_(B)).

Certain aspects encompass a method including separating fluid flowingthrough a wellbore into an internal fluid flowing internal to avolumetric well flow meter and an external fluid flowing external to thevolumetric well flow meter, measuring differential pressures in theinternal fluid and in the external fluid, and determining one or morefluid properties of the fluid flowing through the wellbore based, inpart, on the measured differential pressures.

The aspects above can include some, none, or all of the followingfeatures. The method includes homogenizing the fluid flowing through thewellbore before separating the fluid flowing through the wellbore intothe internal fluid and the external fluid. Measuring differentialpressures in the internal fluid and in the external fluid includes usingdifferential pressure sensors in the volumetric well flow meter. Themethod includes determining one of flow rate, fluid density, or flowpath resistance of the fluid from the measured differential pressures ofthe internal fluid, external fluid, and combined fluid.

Certain aspects encompass a well flow meter system including a means forsplitting well fluid through a wellbore into an internal fluid through avolumetric flow meter and an external fluid through an annulus betweenthe wellbore and the volumetric flow meter. The well flow meter systemincludes a means for sensing a pressure differential of the internalfluid, a means for sensing a pressure differential of the externalfluid, a means for receiving pressure signals of the internal fluid andthe external fluid, a means for determining pressure differentialsacross the internal fluid through the volumetric flow meter and acrossthe external fluid through the annulus, and a means for determiningfluid characteristics of the well fluid based on the determined pressuredifferentials.

The aspects above can include some, none, or all of the followingfeatures. The well flow meter system includes a means for comminglingthe internal fluid and the external fluid that flow past an outlet endof the volumetric flow meter. The well flow meter system includes ameans for correcting flow measurement errors introduced by tolerances ofan inner diameter of the wellbore. The well flow meter system includes ameans for homogenizing the well fluid. The well flow meter systemincludes a means for sensing a pressure differential of the commingledinternal fluid and external fluid. The well flow meter system includes ameans for transmitting differential pressure data of the well fluid, anda means for receiving the transmitted differential pressure data of thewell fluid.

The details of one or more implementations of the subject matterdescribed in this disclosure are set forth in the accompanying drawingsand the description below. Other features, aspects, and advantages ofthe subject matter will become apparent from the description, thedrawings, and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic partial cross-sectional view of an example wellsystem.

FIG. 2 is a schematic partial cross-sectional view of an example wellsystem.

FIG. 3 is a schematic partial cross-sectional view of an example flowmeter well tool.

FIG. 4 is a schematic partial cross-sectional view of an example wellflow meter system.

FIG. 5 is a flowchart describing a method for analyzing a fluid flow ina well.

Like reference numbers and designations in the various drawings indicatelike elements.

DETAILED DESCRIPTION

This disclosure describes a flow meter well tool that measures fluidcharacteristics of a fluid in a well, for example, flow rate, fluiddensity, and flow restriction of the fluid flow. The flow meter welltool includes a volumetric well flow meter positioned in a wellbore thatsplits well fluid through the wellbore into an internal fluid internalto the volumetric well flow meter and an external fluid in an annulusbetween walls of the wellbore and the volumetric well flow meter. Thevolumetric well flow meter measures a fluid characteristic (e.g.,pressure differential) of both the internal fluid and the externalfluid. In some implementations, the flow meter well tool splits thefluid flow into multiple separate paths and measures differentialpressures in each path, as described below. The volumetric well flowmeter can be coupled to or part of another downhole well tool (e.g.,downhole pumping unit) or implemented independently downhole to analyzea well fluid flow, for example, a hydrocarbon-containing fluid in aproduction well, a drilling mud fluid in a well being drilled, and/orother fluid flows in a well.

In some implementations, the flow meter well tool can provide continuousmonitoring of well production, downhole pumping unit performance, scaleformation, casing wear, and/or wellbore wear. A flow meter well toolallows for the calculation of flow rate, fluid density, and flow pathresistance that is not dependent on an inner diameter of a wellbore,casing, or liner. A flow meter well tool can correct for measurementvariances from uncertainty in the inner diameter of the wellbore wall orcasing. A flow meter well tool can be integrated into a downhole gauge,or can be implemented independently of downhole gauges. In someimplementations, a flow meter well tool does not require additionalcontrol and/or power lines that may interfere with other downhole gauges(e.g., a pumping unit) when placed between downhole gauges. In someimplementations, a flow meter well tool allows for an assessment offluid properties before the fluid is affected by a pumping unit.

FIG. 1 is a schematic diagram of a well system 100 including a wellbore102 that extends from a surface 104 downward into the Earth into one ormore subterranean zones of interest 106 (one shown). A well string 108is shown as having been lowered from the surface 104 into the wellbore102. In some instances, the well string 108 is a series of jointedlengths of tubing coupled together end-to-end and/or a continuous (i.e.,not jointed) coiled tubing. The well string 108 can make up a drillstring, production string, or other well string used during the lifetimeof a well system. The well string 108 includes a pumping unit 112 and adownhole assembly 110, for example, including a flow meter well tool. Insome instances, the well string 108 does not include the pumping unit112. In some implementations, such as depicted in FIG. 2, the wellsystem 100 includes a liner (not shown) or casing 114 defined by lengthsof tubing lining a portion of the wellbore 102 extending from thesurface 104 into the Earth.

As shown in FIG. 3, an example flow meter well tool 200 that can be usedin the downhole assembly 110 of FIGS. 1 and 2 is shown in across-sectional side view. The example flow meter well tool 200 splits afluid flow in a casing or wellbore (e.g., casing 114 or wellbore 102) ofa well, and analyzes the split fluid flow to determine fluid flowcharacteristics including, e.g., a flow rate, fluid density, a flow pathresistance of the split fluid flow, or other fluid flow characteristics.The example flow meter well tool 200 includes a volumetric well flowmeter 202, a discharge grill component 204, a measurement correctioncomponent 206, and in some implementations, a flow conditioner 208. Allor a portion of the fluid flow flows into an inlet end 210 of thevolumetric well flow meter 202. The volumetric well flow meter 202includes a hollow cylindrical tubing 212 to split the well fluid into aninternal fluid through the volumetric well flow meter 202 and anexternal fluid through an annulus between the volumetric well flow meter202 and the wellbore, casing, or liner. The external fluid flowsalongside the volumetric well flow meter 202 in the annulus. Thedischarge grill component 204 receives the internal flow and comminglesthe internal and external fluid flows into a single, commingled fluidflow that flows alongside the measurement correction component 206.

The hollow cylindrical tubing 212 of the volumetric flow meter 202includes an internal portion 214 with an internal cross-sectional areathat is less than an internal cross-sectional area of the hollowcylindrical tubing 212. In some implementations, the volumetric wellflow meter 202 includes an internal sensor 216 to measure a pressuredifferential in the internal fluid, and an external sensor 218 tomeasure a pressure differential in the external fluid. The volumetricwell flow meter 202 can include additional and/or different sensors. Insome implementations, the volumetric well flow meter 202 can be aventuri meter configured to measure differential pressures in theexternal and internal fluid flows. In certain implementations, thevolumetric well flow meter 202 can be a turbine or orifice configured tomeasure differential pressures in the external and internal fluid flows.

The discharge grill component 204 attaches to an outlet end 220 of thevolumetric well flow meter 202 and commingles the internal fluid and theexternal fluid that flow past the outlet end 220 of the volumetric wellflow meter 202. The discharge grill component 204 includes a tubing 222coupled to the hollow cylindrical tubing 212 at the outlet end 220 ofthe volumetric well flow meter 202. The tubing 222 of the dischargegrill component 204 includes openings 224 through which the internalfluid flows to commingle with the external fluid in the annulus of thewellbore. The openings 224 can include, for example, grill slots,apertures, perforations, and/or other openings to allow the internalfluid to pass through the tubing 222 and merge with the external fluidin the annulus. The openings 224 have an open area greater than or equalto an interior cross-sectional area of the hollow cylindrical tubing 212of the volumetric well flow meter 202, for example, to maintain aconsistent flow area for the internal fluid passing through the openings224. In some implementations, the discharge grill component 204 includesa bull nose 226 in the tubing 222 to bias the internal fluid to flowthrough the openings 224 in the tubing 222 and into the annulus. Thebull nose 226 may be centered in a longitudinal end of the tubing 222 todirect the internal fluid flow through the openings 224 and out of thedischarge grill component 204 and to minimize turbulence of the internalfluid through the discharge grill component 204. For example, the bullnose 226 may include a rounded or tapered shape in the tubing 222 of thedischarge grill component 204 to redirect the internal fluid outwardsthrough the openings 224 in the tubing 222 into the annulus.

The measurement correction component 206 connects to the discharge grillcomponent 204 and corrects flow measurement errors introduced bytolerances of an inner diameter of the wellbore, casing, or lining. Insome implementations, the measurement correction component 206 includesa correction sensor 228 and a tubing section 230 coupled to the tubing222 of the discharge grill component 204. The correction sensor 228measures a pressure differential in the commingled fluid flow in theannulus along a length of the measurement correction component 206. Insome implementations, the measurement correction component 206 mounts toa downhole well tool on an upstream end of the fluid flow, for example,below the downhole well tool with a diameter the same as a diameter ofthe measurement correction component 206.

The flow conditioner 208 homogenizes the well fluid in the wellbore orcasing at the inlet end 210 of the volumetric well flow meter 202. Theflow conditioner 208 comprises conditioner tubing 232 with fins 234,baffles 236, and/or other homogenizing structures to promotehomogenization of the well fluid. The conditioner tubing 232 couples tothe hollow cylindrical tubing 212 at the inlet end 210 of the volumetricwell flow meter 202. FIG. 3 shows the flow conditioner 208 coupled tothe inlet end 210 of the volumetric well flow meter 202. However, insome implementations, the flow conditioner 208 is excluded in the flowmeter well tool 200.

In some implementations, an outer diameter of the volumetric well flowmeter 202, an outer diameter of the discharge grill component 204, andan outer diameter of the measurement correction component 206 are equal(substantially or exactly) to each other. The volumetric well flow meter202, discharge grill component 204, and measurement correction component206 can be longitudinally aligned, for example, along central axis A-A.In certain implementations, a longitudinal length of the volumetric wellflow meter 202 along the central axis A-A is the same (substantially orexactly) as a longitudinal length of the measurement correctioncomponent 206 along the central axis A-A, for example, such that theexternal sensor 218 of the volumetric well flow meter 202 can measure apressure differential over the same length as the correction sensor 228of the measurement correction component 206. In some implementations,the longitudinal lengths of the volumetric flow meter 202 and themeasurement correction component 206 can be different. The volumetricwell flow meter 202 and the measurement correction component 206 can bemade of the same or different material or materials.

The example flow meter well tool 200 can be implemented in a number ofpositions and configurations. In some implementations, the flow meterwell tool 200 is positioned before an intake of a pumping unit (e.g.,downhole ESP, drilling fluid pump, and/or other), with the outlet end220 of the volumetric well flow meter 202 closer to the intake of thepumping unit than the inlet end 210 of the volumetric well flow meter202. For example, the flow meter well tool 200 can analyze a well fluidflow performance before the well fluid is pumped through the pumpingunit. In some examples, before an intake of the pumping unit includesbelow the pumping unit, such as when well fluid flows up a wellboretowards a well surface (e.g., production wells). In some examples,before an intake of the pumping unit includes above the pumping unit,such as when well fluid flows down a wellbore away from the well surface(e.g., wells being drilled). In other implementations, the flow meterwell tool 200 is positioned after an outlet of a pumping unit. Forexample, the flow meter well tool 200 can analyze a well fluid flowperformance after the well fluid is pumped through the pumping unit. Incertain instances, analyzing the well fluid flow performance after thewell fluid is pumped through the pumping unit with the flow meter welltool 200 may provide data on the performance and efficiency of thepumping unit. In some examples, after an outlet of the pumping unitincludes above the pumping unit, such as when well fluid flows up awellbore towards a well surface (e.g., production wells). In someexamples, after an outlet of the pumping unit includes below the pumpingunit, such as when fluid flows down a wellbore away from the wellsurface (e.g., wells being drilled). In further implementations, a flowmeter well tool 200 is positioned in a wellbore as a standalone welltool, for example, excluding a pumping unit.

The flow meter well tool 200 can include additional or differentcomponents and features. For example, the example flow meter well tool200 can include a centralizer at a longitudinal end of the flow meterwell tool 200 to center the flow meter well tool 200 in a wellbore orcasing. In another example, the flow meter well tool 200 can include apower source connected to the flow meter well tool 200, such as aturbine generator, battery, or another power source. A power source cansupply power to the sensors 216, 218, and 228 on the volumetric wellflow meter 202 and measurement correction component 206, and/orelectronic systems associated with the flow meter well tool.

In some implementations, the downhole assembly 110 of FIGS. 1 and 2includes one or more components of the flow meter well tool 200 of FIG.3. For example, FIG. 4 shows an example well flow meter system 300 thatincludes some components of the flow meter well tool 200 of FIG. 3,including the volumetric well flow meter 202, the internal sensor 216,and the external sensor 218. The well flow meter system 300 alsoincludes processing circuitry 302 connected to the internal sensor 216and the external sensor 218 to determine pressure differential data fromthe internal sensor 216 and external sensor 218 and to determine one ormore fluid characteristics based on the pressure differential data. FIG.4 shows the processing circuitry 302 downhole with the flow meter welltool 200 in a well. In certain implementations, the processing circuitry302 is located uphole of the flow meter well tool 200, for example, atthe surface of the well, and connected to the internal sensor 216 andthe external sensor 218 via a wired, wireless, a combination of wiredand wireless connection, and/or another connection. In someimplementations, the well flow meter system 300 includes a dischargegrill component 204 and a measurement correction component 206,including a correction sensor 228 of the measurement correctioncomponent 206. The processing circuitry 302 can assess pressuredifferential data from the correction sensor 228 in addition to pressuredifferential data from the internal sensor 216 and external sensor 218.In certain implementations, the well flow meter system 300 includes acomputer readable storage medium storing instructions executable by oneor more processors as an alternative to or in addition to the processingcircuitry 302.

In some implementations, the processing circuitry 302 connects to atransmitter electronically coupled to the internal sensor 216, theexternal sensor 218, and the correction sensor 228, and a receiverconfigured to receive differential pressures from the transmitter. Insome examples, the transmitter is mounted on the volumetric flow meter202, measurement correction component 206, and/or another component, andthe receiver is located at a surface of the respective well. In someimplementations, the processing circuitry 302 comprises a processor toassess data and calculate the fluid characteristics based on thepressure differentials. The fluid characteristics that the processingcircuitry 302 determines can vary. In some examples, the fluidcharacteristics include one or more of a volumetric flow rate (Q) of thecommingled fluid, a volumetric flow rate (Q_(A)) of the internal fluid,a volumetric flow rate (Q_(B)) of the external fluid, a fluid density(ρ), and a fluid flow path resistance (R_(B)). The fluid characteristicscan be determined from the differential pressures determined from thesensors of the well flow meter system 300. In certain instances, thefollowing set of equations are used to solve for the fluidcharacteristics:

$\begin{matrix}{Q_{A} = {A_{1}\sqrt{\frac{2\Delta \; P_{12}}{\rho \lbrack {( \frac{A_{1}}{A_{2}} )^{2} - 1} \rbrack}}}} & (1) \\{Q = {Q_{A} + Q_{B}}} & (2) \\{{\Delta \; P_{xy}} = {( {{R_{B}Q_{B}^{2}} + H_{g}} )\rho \; g}} & (3) \\{{\Delta \; P_{xy}} = {( {{R_{A}Q_{A}^{2}} + H_{g}} )\rho \; g}} & (4) \\{{\Delta \; P_{ij}} = {( {{R_{B}Q^{2}} + H_{g}} )\rho \; g}} & (5)\end{matrix}$

The set of equations define a solvable set of five equations with 5unknowns, where the five unknowns are Q, Q_(A), Q_(B), ρ, and R_(B), asdescribed above. The variables in the above equations are defined inTable 1, below. The fluid characteristics can be determined by theprocessing circuitry 302 from the equations.

TABLE 1 Variable Definition Q volumetric flow rate of commingled fluidQ_(A) volumetric flow rate of internal fluid Q_(B) volumetric flow rateof external fluid A₁ internal cross-sectional area of volumetric wellflow meter A₂ internal cross-sectional area of internal portion ofvolumetric well flow meter ΔP₁₂ pressure differential in the volumetricwell flow meter from the internal sensor, from the inlet end to theinternal portion ρ fluid density R_(A) fluid flow path resistance of thefluid through the volumetric flow meter R_(B) fluid flow path resistanceof the annulus at the volumetric well flow meter H_(g) verticalelevation change of the external sensor, and/or of the correction sensorΔP_(xy) pressure differential from the external sensor, from the inletend to the outlet end of the volumetric well flow meter ΔP_(ij) pressuredifferential from the correction sensor, from one end of the measurementcorrection component to another end

FIG. 5 is a flow chart describing a method 400 of analyzing a fluid in awell, for example, performed by the example well flow meter tooldescribed above. At 402, a fluid flowing through a wellbore is separatedinto an internal fluid flowing internal to a volumetric well flow meterand an external fluid flowing external to the volumetric well flowmeter. At 404, differential pressures are measured in the internal fluidand in the external fluid. At 406, one or more fluid properties of thefluid flowing through the wellbore are determined based, in part, on themeasured differential pressures. In some examples, processing circuitrycan implement the method 400, specifically step 406 of determining oneor more fluid properties of the fluid flowing through the wellbore. Theprocessing circuitry can be implemented uphole, downhole, or at a remotelocation away from a respective well site.

A number of implementations have been described. Nevertheless, it willbe understood that various modifications may be made without departingfrom the spirit and scope of the disclosure.

What is claimed is:
 1. A flow meter well tool comprising: a volumetricwell flow meter to be positioned in a wellbore, the volumetric well flowmeter comprising: a hollow cylindrical tubing to be positioned in thewellbore, the tubing to split well fluid through the wellbore into aninternal fluid through the volumetric well flow meter and an externalfluid through an annulus between the wellbore and the volumetric wellflow meter, the hollow cylindrical tubing comprising an internalportion, wherein an internal cross-sectional area of the internalportion is less than an internal cross-sectional area of the hollowcylindrical tubing.
 2. The flow meter well tool of claim 1, furthercomprising a discharge grill component attached to an outlet end of thevolumetric well flow meter, the discharge grill component to comminglethe internal fluid and the external fluid that flow past the outlet endof the volumetric well flow meter.
 3. The flow meter well tool of claim2, wherein the discharge grill component comprises a tubing attached tothe hollow cylindrical tubing at the outlet end of the volumetric flowmeter, the tubing comprising openings through which the internal fluidflows to commingle with the external fluid.
 4. The flow meter well toolof claim 3, where an open area of the openings is greater than or equalto the internal cross-sectional area of the hollow cylindrical tubing ofthe volumetric flow meter.
 5. The flow meter well tool of claim 3,wherein the discharge grill component further comprises a bull nose inthe tubing.
 6. The flow meter well tool of claim 2, further comprising ameasurement correction component attached to the discharge grillcomponent, the measurement correction component to correct flowmeasurement errors introduced by tolerances of an inner diameter of thewellbore.
 7. The flow meter well tool of claim 6, wherein an outerdiameter of the volumetric well flow meter, an outer diameter of thedischarge grill component, and an outer diameter of the measurementcorrection component are substantially equal to each other.
 8. The flowmeter well tool of claim 6, wherein a longitudinal length of thevolumetric well flow meter is substantially the same as a longitudinallength of the measurement correction component.
 9. The flow meter welltool of claim 1, further comprising a flow conditioner at an inlet endof the volumetric well flow meter to homogenize the well fluid.
 10. Theflow meter well tool of claim 9, wherein the flow conditioner comprisesa conditioner tubing with a plurality of fins arranged to homogenize thewell fluid, the conditioner tubing coupled to the hollow cylindricaltubing at the inlet end of the volumetric well flow meter.
 11. The flowmeter well tool of claim 1, wherein the volumetric well flow meter ispositioned before an intake of a downhole pumping unit in the wellbore.12. A well flow meter system, comprising: a volumetric well flow meterpositioned in a wellbore, the flow meter comprising a hollow cylindricaltubing to split well fluid through the wellbore into an internal fluidthrough the volumetric flow meter and an external fluid through anannulus between the wellbore and the volumetric well flow meter; aninternal sensor of the hollow cylindrical tubing to measure a pressuredifferential of the internal fluid; an external sensor of the hollowcylindrical tubing to measure a pressure differential of the externalfluid; and processing circuitry connected to the internal sensor and theexternal sensor, the processing circuitry to perform operationscomprising: receiving pressure signals from the internal sensor and theexternal sensor; determining pressure differentials across the internalfluid through the volumetric flow meter and across the external fluidthrough the annulus; and determining fluid characteristics of the wellfluid based on the determined pressure differentials.
 13. The well flowmeter system of claim 12, wherein the hollow cylindrical tubingcomprises an internal portion, the internal portion having across-sectional area less than an internal cross-sectional area of thehollow cylindrical tubing.
 14. The well flow meter system of claim 12,further comprising: a discharge grill component attached to an outletend of the volumetric well flow meter, the discharge grill component tocommingle the internal fluid and the external fluid that flow past theoutlet end of the volumetric well flow meter; and a measurementcorrection component comprising: a tubing section; and a correctionsensor to measure a pressure differential of the commingled internal andexternal fluid between the measurement correction component and thewellbore.
 15. The well flow meter system of claim 14, furthercomprising: a transmitter electronically coupled to the internal sensor,the external sensor, and the correction sensor; and a receiver toreceive differential pressure data from the internal sensor, theexternal sensor, and the correction sensor, the differential pressuredata transmitted from a transmitter coupled to the internal sensor, theexternal sensor, and the correction sensor.
 16. The well flow metersystem of claim 14, wherein the operations further comprise determininga pressure differential across the commingled internal fluid andexternal fluid flowing outside the correction sensor; and wherein thefluid characteristics comprise a volumetric flow rate of the commingledfluid, a volumetric flow rate of the internal fluid, a volumetric flowrate of the external fluid, a fluid density, and a fluid flow pathresistance.
 17. The well flow meter system of claim 16, whereindetermining the fluid characteristics of the well fluid comprisessolving the following equations:$Q_{A} = {A_{1}\sqrt{\frac{2\Delta \; P_{12}}{\rho \lbrack {( \frac{A_{1}}{A_{2}} )^{2} - 1} \rbrack}}{\quad {Q = {{Q_{A} + {Q_{B}{\Delta \; P_{xy}}}} = {{( {{R_{B}Q_{B}^{2}} + H_{g}} )\rho \; g{\Delta \; P_{xy}}} = {{( {{R_{A}Q_{A}^{2}} + H_{g}} )\rho \; g\Delta \; P_{ij}} = {( {{R_{B}Q^{2}} + H_{g}} )\rho \; g}}}}}}}$wherein an internal cross-sectional area of the volumetric flow meter(A₁), the pressure differential of the internal fluid (ΔP₁₂), smallestinternal cross-sectional area of an internal portion of the volumetricflow meter (A₂), the pressure differential of the external fluid(ΔP_(xy)), the pressure differential of the commingled fluid (ΔP_(ij)),flow path resistance of the fluid through the volumetric flow meter(R_(A)), and vertical elevation change (H_(g)) are used to solve forvolumetric flow rate of the commingled fluid (Q), volumetric flow rateof the internal fluid (Q_(A)), volumetric flow rate of the externalfluid (Q_(B)), fluid density (ρ), and fluid flow path resistance(R_(B)).
 18. A method, comprising: separating fluid flowing through awellbore into an internal fluid flowing internal to a volumetric wellflow meter and an external fluid flowing external to the volumetric wellflow meter; measuring differential pressures in the internal fluid andin the external fluid; and determining one or more fluid properties ofthe fluid flowing through the wellbore based, in part, on the measureddifferential pressures.
 19. The method of claim 18, further comprising:commingling the internal fluid and the external fluid into a combinedfluid; and measuring a differential pressure in the combined fluid. 20.The method of claim 18, further comprising homogenizing the fluidflowing through the wellbore before separating the fluid flowing throughthe wellbore into the internal fluid and the external fluid.
 21. Themethod of claim 18, wherein measuring differential pressures in theinternal fluid and in the external fluid comprises using differentialpressure sensors in the volumetric well flow meter.
 22. The method ofclaim 19, further comprising determining one of flow rate, fluiddensity, or flow path resistance of the fluid from the measureddifferential pressures of the internal fluid, external fluid, andcombined fluid.